# Quote — Carl Sagan, Cosmos

> There is no other species on the Earth that does science. It is, so far, entirely a human invention, evolved by natural selection in the cerebral cortex for one simple reason: it works. It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. We must understand the Cosmos as it is and not confuse how it is with how we wish it to be.

- Author: [Carl Sagan](https://www.leafyquotes.com/carl-sagan.md)
- Book: [Cosmos](https://www.leafyquotes.com/carl-sagan/cosmos.md)
- Page: 333
- Source: [Wikiquote](https://en.wikiquote.org/wiki/Carl_Sagan#Cosmos_(1980)) ([CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/))
- Quote page: https://www.leafyquotes.com/carl-sagan/cosmos/there-is-no-other

## More from this book

> I have...a terrible need...shall I say the word?...of religion. Then I go out at night and paint the stars.

p. 217 — [Quote page](https://www.leafyquotes.com/carl-sagan/cosmos/i-have-a-terrible.md)

> For a long time the human instinct to understand was thwarted by facile religious explanations.

p. 173 — [Quote page](https://www.leafyquotes.com/carl-sagan/cosmos/for-a-long.md)

> If you wish to make an apple pie from scratch, you must first invent the universe.

p. 218 — [Quote page](https://www.leafyquotes.com/carl-sagan/cosmos/if-you-wish.md)